Analgesic Efficacy of Adding Different Doses of Dexmedetomidine as Adjuvants With Bupivacaine vs.Bupivacaine Only in Ultrasound-guided Erector Spinae Plane Block in Morbidly Obese Patients Undergoing Laparoscopic Bariatric Surgery. A Randomized Controlled Double Blinded Study.

Inclusion Criteria: * Age starting from 21 to 60 years. * Genders eligible for study: Male and female sexes. * ASA I-III * Undergoing Laparoscopic bariatric surgery. * BMI \> = 40. Exclusion Criteria: * Patient refusal * Known allergy to local anesthetics and adjuvant drugs used (dexamedatomedine) * Bleeding disorders; platelets count \<50,000, prothrombin concentration \< 60% or any coagulopathy disorder. * Use of any anti-coagulants * Inability to provide informed consent * ASA -IV * Neurological disorders * Patient with psychiatric disorders * Failed block is claimed if the patient required more than 2 doses of rescue analgesia in the first 2 hrs post operative , failed block cases will be recorded , excluded and managed according to the institutional regulations (opioid analgesia).